What viscosity oil do you all use?
I know that the M.O.M. recommends 10w-40, but I am considering a synthetic 20w-50 to keep my engine cooler in this Texas heat and the DFW stop and go traffic. I noticed that my exhaust pipe is discoloring at the elbow into a deep gold almost purple. I know that some discolorization is normal, but I feel that this one is a little premature (2000miles on odometer) and is probably the result of overheating. BTW I checked the plug -good color there, not running rich; stock exhaust and main jets. I can only assume that maybe a lower viscosity oil was put in there like a 10w-30 or lower. My concern is how the oil film thickness of a higher viscosity oil may effect a Savage. I have heard the following:

“It is best to use the lowest viscosity possible which will provide the proper separation of metal. Anything more than this will increase power loss due to friction and will reduce the pumpability of the oil at all temperatures. If clearances are tight and very little lugging occurs use 5w30 or 10w30. Also lower viscosity oil will flow better and lubricate the engine more quickly at start-up. If ambient temperatures will regularly climb over 100deg F, then use 10w-40. If the engine is air-cooled, or if the engine is older and has greater bearing and ring clearances, then use 20w-50 since it will develop a thicker oil film. However 20w-50 is not recommended for street use in production engines that see sustained oil temperatures below 225°F.”

The way I understand this is that with higher viscosity oils, the thicker oil film will not be able to ”squeeze  itself “ between metal parts were the most friction occurs as well as a 10w-30, but it is good  for higher temperatures.
What temperature ranges do our Savages run in?
I don’t think that the Savage has as tight clearances as say some high RPM sport bikes, and the loss of power may not be an issue, but for those of you that have used 20w-50: Have you witnessed any power loss?

> The way I understand this is that with higher viscosity
> oils, the thicker oil film will not be able to ”squeeze
>  itself “ between metal parts.....as a 10w-30

Higher viscosity oils may not move around well enough for a 14K rpm sport bike, but I would not be too concerned about flow with these slow turning, ball bearing thumpers.


> I don’t think that the Savage has as tight clearances
> as say some high RPM sport bikes

Air cooled engines do have slightly lower piston/cylinder tolerances than regulated-temp H20 engines to allow for a wider expansion and contraction range.

> 20w-50: Have you witnessed any power loss?

I doubt you'll sense power loss from a 20w-50 in a 650 single. A straight 50w might slow acceleration a bit, though.

Use a wide-range synthetic like Mobil-1 15w-50 and the engine will rev easier, shift smoother, and run a little quieter.  

Good info.
I’ll hold off on the synthetic till later, but how much later?
At what mileage is the engine fully broken-in and the rings seated?
What do you all think about the statement of not using 20w-50 in engines that do not reach at least 225degF?
Does the Savage reach that temperature?
As always, thanks for all your good input  

SH and later car oils have additives to help economy and emmisions, that don't agree with 'bike engines.

Clive W

Quote:


Au contraire mon frere,  I used it for about 14 days and the clutch did slip.  I could be idling along in 1st and the bike would be going slower and slower while the revs would be slowly going higher and higher and higher...  It was an odd sensation the first time I noticed it.

???

Gitarzan wrote on 12/31/69 at 16:00:08:


I noticed it when releasing the clutch under a load such as going up a hill.  After I switched back, it stopped.  I'll try a motorcycle specific synthetic next time.

The rule of thumb for Mobil 1 is the red cap stuff does not have the same friction modifiers in it as the green cap stuff. Many have complained about slippage w/ green caps stuff.
Also the stock exhaust is quite restrictive. If you have replaced the pipe and re-jetted there is a good 20% power increase to be had.
Just like when I added the Denco heads and chambers to my old triple, it had not had an easy life and the hop-up ran through the clutch, (non-synthetic oil) but it needed to be slipped more than a tractor-like LS650.
This will heat the whole pack up and kill the springs if you really dog it at test and tune night.
I would expect you might experience slippage sooner rather than later if the bike has been re-piped and re-jetted. How/where you ride, how much power and how many miles all figure in, before you pour in the Synthetics. If it is a problem, swap back to no-synth. and/or start checking places like Barnett for stiffer springs if the discs & floaters are all OK. An inventive guy might just find some thin washers to shim his stock springs, watch out for coil bind though. I would not let a set of springs keep me from using synethics. Also Mobile 1 now has a 20W-50 V-twin and 10W-40 motorcycle oils check it at their site;
http://www.mobil1.com/motorcycle/index.jsp

Think you dealer would let you rumage around and compare your stockers to something from other/larger Suzys?